pays attention to something in the left side of the visual field, an N2pc appears as a greater negativity over the right posterior areas of the brain than the left. MEG has been used to localize the N2pc primarily to lateral extrastriate cortex and inferotemporal visual areas, such as V4. Classic paradigms and findings The N2pc can be used flexibly in nearly any task in which one would like to study the direction and time course of selective attention. However, researchers have primarily used the N2pc in visual search paradigms to study the deployment of attention over time and test hypotheses of parallel and serial models of visual search. The first experiments to investigate specifically the N2pc used a visual search paradigm in which subjects reported the presence or absence of a pre-defined target (e.g., a green rectangle) in a display containing one "oddball" stimulus that differed on a single feature from a uniform background of items (e.g., a green square among blue squares). The oddball stimuli would "pop out" and attract attention, but were not necessarily targets. As a result, experimenters knew where subjects directed attention, but could simultaneously manipulate factors orthogonal to the location of attention, such as low-level features or probability of the target appearing. The pop-out oddball would generate an N2pc, as it received focused attention, while stimulus characteristics modulated the amplitude and latency of the component. Subsequent investigation into the N2pc manipulated the number of items in the array and found that a display with as few as two objects elicits the component. Because an object cannot "pop out" and attract attention in a two-item display, experimenters concluded that the N2pc must reflect top-down, controlled processes of directing attention. The same study also demonstrated that the N2pc does not only occur when attending to visual features, but semantic features as well. In one experiment, subjects had to respond to the words "left" and "right" while ignoring the color words "white" and "brown." Even in this case of semantically defined targets, subjects demonstrated an N2pc contralateral to the target word. Together, these results have provided strong evidence that the N2pc reflects the location of covert, consciously directed attention. The prototypical visual search paradigm for eliciting an N2pc component has subjects attend and respond to a target stimulus to the left or right of fixation. Unlike regular visual search experiments, however, two major criteria most hold when